The growing demand for alternative options in display assemblies, has allowed the market to respond with several options. These options have created certain confusion within the industry on what the differences are such as quality, brightness, possible issues, and more.

While many of them might look alike, the structure might differ greatly which has an impact on price. These two main structures are COF and COG.

Let’s take a deeper look into what the similarities and differences are between COF and COG.

What is COF & COG

COG: Chip on Glass, is the most traditional screen packaging technology and the most cost-effective solution, and is widely used. Before the trend of full screen, most mobile phones adopted COG screen packaging technology.

COF: Chip on Flex, this packaging technique is to place the screen's IC chip on a flexible FPC and then bend it to the bottom. Compared with the COG solution, the frame can be further reduced and the screen ratio can be increased.

What is the differences between COF and COG ?

The drive IC in different places

From the naming of the two processes, we can clearly know that IC positions are different. What will be the impact of the drive IC in different places on the screen?

Take Huawei 9P as an example, the COG technology is to put the driver IC on the bottom of the glass and connect to the flex cable then bend it, this situation, will definitely occupy the screen window and lose part of the chin size of the screen.

Glass of same size, COF technology is to put the driver IC on the flex cable directly, and then fold the flex cable over which can be placed under the screen bottoms. In this way, IC doesn’t need to occupy the screen. And can maximize the screen window.

The technical differences cause the price differences

COF is kind of mature technique, but for upstream aftermarket, there is a certain gap with powerful factories in terms of equipment and production technology. Therefore, the production yield of COF is relatively low, the better one may reach 90%, and the worse one is only 70% or 80%.

So this will affect the production cost of the screen, resulting in a higher final screen price.

COG is a very mature technique. COG scheme has a relative higher production yield and lower production cost. So in terms of production, COG scheme has a cost and price advantage.

Screen window proportion:  COF >COG

The screen ratio of COF is slightly larger than that of COG. COF is looks more like original quality.

Screen Display

The main factors that influence screen brightness and color are glass and backlight. It has no relations with whether the screen is COF or COG.

Screen touch

It is determined by its software data. If there is no problem with the software solution data, there is no difference in the touch stability between COG and COF.


COF Screen more easier break inside, because the chip is on the flex, and the flex is soft, so easy to broken the screen when doing installation. COG screen is more durable.

According to the above analysis, you should have a certain understanding of COF and COG. Choose a more suitable screen according to your needs.

Be noted that the ability to distinguish needs to be improved, because many manufacturers on the market will use COG to impersonate COF.

In the repair and aftermarket market, there are many existing COG screens, and the quality is also uneven. The process and materials used are different, and there will be differences in display effects.

TX Electronics has always been committed to providing customers with quality products. All of our screens are produced according to strict standard, test more than 3 times before shipments. With low defective rate, high brightness, true color reproduction, more stable quality, and high cost performance, which have won praise from our customers.

If you want to know more about the quality analysis and get the latest quotation of the screen, please contact us, we will answer you as soon as possible.